B23K26/1476—Features inside the nozzle for feeding the fluid stream through the nozzle

Abstract

PURPOSE:To cut precisely a thick material to be worked as well by a laser by sealing gaseous oxygen flow flowing out coaxially with laser light from the atm. air by fluid having small density. CONSTITUTION:A high flow rate of gaseous oxygen 3 is ejected from a nozzle 2 together with laser light 1. The 2nd nozzle 11 is attached to the nozzle 2 and fluid 13 having the density smaller than the density of air such as gaseous He 12 or the like is ejected therefrom to shield the gaseous oxygen flow 3 against the atm. air during cutting of a material 4 to be worked by a laser. The frictional force occuring in the difference in flow rate between the gaseous oxygen flow 3 and the atm. pressure is thus decreased. As a result the decrease in the flow rate and concn. of the gaseous oxygen flow 3 is prevented and the precision cutting is satisfactorily accomplished.